The present invention relates to a pneumatic tire for off-road motorcycle, more particularly to a block tread pattern capable of improving transitional characteristics during cornering and the traction performance on rough terrain.
Japanese Patent Application Publication No. 2009-67245 (hereinafter the patent document 1) discloses a pneumatic tire for running on rough terrain which is a directional tire provided in the tread portion with crown blocks disposed on the tire equator, and middle blocks disposed on each side of the crown block in the tire axial direction. The drawings of the patent document 1 show that the middle blocks are arranged with different circumferential pitches from those of the crown blocks, and some of the crown blocks are aligned in line in the tire axial direction with some of the middle blocks.
Therefore, when the tread portion is deflected in the ground contacting patch, the aligned crown block and middle block are liable to contact with each other and to act as if one block. In such case, for example, it becomes difficult to lean the motorcycle body to initiate turning, and if the lean angle increases over a certain value, the motorcycle body is abruptly leant. Thus, there is a problem with transitional characteristics during cornering.